gaming motherboard with multiple gpu slots

(A lane is a single send/receive line of data. The PCI Express electrical interface is measured by the number of simultaneous lanes. More recent revisions of the PCIe standard provide hardware support for I/O virtualization. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER), and native hot-swap functionality. It is the common motherboard interface for personal computers' graphics cards, sound cards, hard disk drive host adapters, SSDs, Wi-Fi and Ethernet hardware connections. How many lanes will each GPU require? I will be using one GTX 1080 and two GTX 1080ti and want to keep my GTX 1060 just like it is.PCI Express ( Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. How can I tell how many lanes are available on the motherboard? I know the CPU has 16 PCIe lanes but I can't find anything on the motherboard. Many people have said it worked for them but it will depend on the PCIe lanes available in the motherboard/CPU. From what I have read online, there isn't any clear answer on whether this is possible. There is already a GTX 1060 3GB GPU installed in the PCIe x16 slot and I would like to use the additional PCIe x1 slot with a PCIe expander to add an additional 3 GPUs with a separate power supply for mining cryptocurrencies. I currently have an HP Omen (Windows 10) with the Odense2-K motherboard and an i5-7400. Essentially I am having trouble understanding what is possible from the PCIe standpoint. Essentially, I want to limit the upfront cost of my investment and therefore I would like to use my current desktop as the mining platform (it will save me from buying another cpu, motherboard, HD, RAM, etc.). As the title suggests, I am looking to expand my current computer to have multiple GPUs (for mining).

Gaming motherboard with multiple gpu slots